Add logic in run_tests.sh for *-rdo branches
Add logic in run_tests.sh for *-rdo branches

https://trello.com/c/URAtrhLU/86-automate-stable-packages-releases
states that, from stable/newton on, distgit branches for stable
releases will be '*-rdo' rather than 'rpm-* as now. We need to
support both styles in our CI scripts.

Change-Id: I0ed5a17ecc35e2e34f06209b31a5638ccec42456

openstack-packages/delorean,openstack-packages/delorean,openstack-packages/DLRN,openstack-packages/DLRN